Question

The momentum of a photon having energy equal to the rest energy of an electron is

• A. Zero
• B. $2.7\times {10}^{-22}kgm{s}^{-1}$
• C. $1.99\times {10}^{-24}kgm{s}^{-1}$
• D. $\infty$

Answer 1

The correct option is B $2.7\times {10}^{-22}kgm{s}^{-1}$

Momentum of a particle having rest mass energy zero like photon is given by:
$E=pc$, where p is the momentum and c is the speed of the photon.
So, $p=E/c=\frac{m_0{c}^2}{c}=m_{0}c=2.7\times {10}^{-22}$

So, the answer is option (B).